1. Field of the Invention
The present invention relates to a composition for facial contouring, comprising a mixture of botulinum toxin and air, and a method of facial contouring using the same.
2. Description of the Related Art
In the human musculoskeletal system, each muscle including origin and insertion points is originated from a bone and attached to another bone, and thus the muscles control the movement of the musculoskeletal system by their movement. Meanwhile, unlike the body's musculoskeletal system, facial muscles are originated from the facial skeleton and attached to the skin to make facial expressions. Facial skin consists of several different layers, and each with a specialized function. The major skin layers include the epidermis, the dermis, and the hypodermis. A very thin fibromuscular layer, which is known as the superficial muscular aponeurotic system (hereinafter referred to as SMAS), is present between the subcutaneous fat layer and the muscular layer under the hypodermis, and all the fascia of the muscles of facial expression, the facial ligaments, and the subcutaneous fibrous tissues are fused to form a single thin layer over the face and the head. Histological observation of the SMAS layer shows that there are fibroblasts, myocytes, collagen, elastin, polysaccharides, etc. Therefore, the SMAS layer serves to uniformly connect whole facial muscles to the dermis and, at the same time, has a membrane structure distributed over the face and the head to connect various facial muscles to allow several muscles to make one facial expression in an integrated fashion. The SMAS layer becomes thinner with age, which makes wrinkles and causes the skin to sag. In general, the lifting procedure is performed to improve the sagging of the face by incising, pulling, and suturing the SMAS layer, but it causes side effects caused by anesthesia for surgery, side effects such as scars after surgery, and disturbance of daily life after surgery.
Botulinum toxin (also known as botulin toxin or botulinum neurotoxin) is a neurotoxin produced by the gram-positive bacteria Clostridium botulinum. Botulinum toxin produces paralysis of muscles by preventing synaptic transmission or release of acetylcholine across the neuromuscular junction and is thought to act in other ways as well. Botulinum toxin essentially blocks signals that normally would cause muscle spasms or contractions, resulting in paralysis. Botulinum toxin is classified into eight neurotoxins that are serologically related, but distinct. Of these, seven can cause paralysis, namely botulinum neurotoxin serotypes A, B, C, D, E, F and G. Among others, serotypes A and B are clinically used for the treatment of various diseases and wrinkles. Each of these is distinguished by neutralization with type-specific antibodies. Nonetheless, the molecular weight of the botulinum toxin protein, for all seven of these active botulinum toxin serotypes, is about 150 kD. The botulinum toxin secreted by bacteria is complexes comprising the 150 kD botulinum toxin protein molecule along with associated non-toxin proteins. The botulinum toxin type A complex can be produced by Clostridium bacteria as 900 kD, 500 kD and 300 kD forms. Botulinum toxin types B and C are apparently produced as only a 700 kD or 500 kD complex. Botulinum toxin type D is produced as both 300 kD and 500 kD complexes. Finally, botulinum toxin types E and F are produced as only approximately 300 kD complexes. The complexes (i.e. molecular weight greater than about 150 kD) are believed to contain a non-toxin hemaglutinin protein and a non-toxin and non-toxic nonhemaglutinin protein. These two non-toxin proteins may act to provide stability against denaturation to the botulinum toxin molecule and protection against digestive acids when toxin is ingested. Additionally, it is possible that the larger (greater than about 150 kD molecular weight) botulinum toxin complexes may result in a slower rate of diffusion of the botulinum toxin away from a site of intramuscular injection of a botulinum toxin complex. The different serotypes of botulinum toxin vary in the animal species that they affect and in the severity and duration of the paralysis they evoke. For example, it has been determined that botulinum toxin type A is 500 times more potent, as measured by the rate of paralysis produced in the rat, than is botulinum toxin type B. Additionally, botulinum toxin type B has been determined to be non-toxic in primates at a dose of 480 U/kg, about 12 times the primate LD50 for type A. Due to the molecular size and molecular structure of botulinum toxin, it cannot cross the stratum corneum and the multiple layers of the underlying skin architecture.
Botulinum toxin type A is said to be the most lethal natural biological agent known to man. Spores of C. botulinum are found in soil and can grow in improperly sterilized and sealed food containers. Ingestion of the bacteria can cause botulism, which can be fatal.
Meanwhile, facial contouring is a procedure to correct the facial contour by adjusting facial bones, and a method of cutting bones using a bone cutting saw has been conventionally used for the facial contouring. However, according to this method, a large bone should be cut, and a large amount of bones is cut at a time, which has a problem of accuracy. Therefore, in order to accurately determine the cutting angle, easily remove bone fragments, and facilitate the access to the cutting site, it is necessary to ensure the visibility, which requires large incision area, resulting in various problems such as severe swelling, severe bleeding, delayed healing, cut vessels, damaged nerves, etc. Moreover, the bone cutting saw may cause severe injury to the surrounding soft tissues during operation.
Moreover, for the same purpose, there is a method of using a file in which an adaptor with a converting mechanism for converting rotational motion to rectilinear motion is coupled to a powered surgical handpiece, a cutting element such as a file is coupled to the adaptor, an inlet is formed on the cutting surface of the file, a suction tube is coupled to the inlet, and the cutting element formed on an end of an elongated shaft is inserted into skin to cut bones for facial contouring. This method can solve various problems that may occur when the bone cutting saw is used, but cannot be effectively used in most bone cutting procedures performed using conventional saws such as facial contouring for angular chins or collection of bones for transplantation.
Meanwhile, the muscle-paralyzing effects of botulinum toxin have been used for therapeutic effects on various conditions such as hemifacial spasm, adult onset spasmodic torticollis, anal fissure, blepharospasm, cerebral palsy, cervical dystonia, migraine headaches, strabismus, temporomandibular joint disorder, and various types of muscle cramping and spasms. More recently, the muscle-paralyzing effects of botulinum toxin have been used in therapeutic and cosmetic facial applications such as treatment of wrinkles, frown lines, and other results of spasms or contractions of facial muscles. However, no method of facial contouring using botulinum toxin has been reported.
Accordingly, the present inventors have studied the applicability of botulinum toxin, which has been used for the treatment of various diseases, to existing methods of facial contouring and found that when the SMAS layer is selectively paralyzed by injecting a mixture of botulinum toxin and air into the SMAS layer, the mobility of untreated adjacent SMAS layer is strengthened, which in turn draw back the galea aponeurotica to effectively lift up the face or change the facial contour, which provides an enhanced effect of facial contouring, thus completing the present invention.